Pakistanis are voting in parliamentary elections that will mark the first time in the country's history that a civilian government has finished its term and handed over power to another civilian government.
Pakistani politician and former cricketer Imran Khan is leading the PTI party and posting a challenge to the two parties that long dominated Pakistani politics. But Khan, who is popular with Pakistan's younger voters, suffered a fall earlier this week and now lies flat on his back in a hospital, not able to make campaign appearances.
Former prime minister Nawaz Sharif leads the Pakistan Muslim League, which is expected to take the majority of votes as candidates compete for 272 seats in the National Assembly.
Public opinion polls indicate that the Pakistan People's Party is trailing behind its two competitors. The PPP's most prominent member is President Asif Ali Zardari, widower of assassinated former prime minister Benazir Bhutto.
Winners of seats in Saturday's parliamentary elections will be tasked with leading a country suffering from periodic power failures, a poor economy, a Taliban insurgency and political corruption.
Bombings on Friday killed at least four people and wounded 18 others.
The four died in a blast near political party offices in North Waziristan - a Taliban and al-Qaida stronghold. Thirteen people were wounded.
A blast in the southwestern part of the country wounded five more people outside an office being used by the Pakistan People's Party.
No one has claimed responsibility for the bombings, but the Taliban has carried out numerous attacks to undermine the polls and says it has dispatched suicide bombers for the national election. More than 100 people have been killed and scores wounded since late April.
Pakistan's military says it is deploying thousands of troops to polling stations and counting centers.
The recent bombings of two rallies of a leading Islamic party, Jamiat Ulema-e-Islam, strengthened views the Taliban is opposed to democracy and is targeting anyone taking part in the elections.
On Thursday, the last day of campaigning, militants kidnapped Ali Haider Gilani in Punjab province. The son of former prime minister Yousuf Raza Gilani is running for a provincial assembly seat.